These 13 images provide an inside look at Shoreline Amphitheatre in Mountain View, Calif., the site of Google's 2016 I/O developer conference, as well as some other quirky scenery at I/O.

Google this week held its annual developer conference right next door to its headquarters in Mountain View, Calif., at the massive, storied Shoreline Amphitheatre. More than 6,500 people attended the outdoor keynote address, which felt a bit like an early morning rave, complete with thundering bass, trippy imagery and ambient sound.

At the registration desk, I/O attendees received all kinds of swag, including Google's Cardboard VR headset, a water bottle, a head wrap, sunscreen and shades — omens of the heat that came later in the day.

During the opening keynote, Google CEO Sundar Pichai introduced the company's Google Assistant, a new platform that blends AI and machine learning to provide more contextual responses and automated action. "We want users to have an ongoing, two-way dialogue with Google," he said. "We think of this as building each user their own individual Google."

Google's Vice President of Product Management Mario Queiroz revealed the Google Home voice assistant device during the opening I/O keynote. The device is expected to ship later this year, and it will compete directly with Amazon's Echo assistant.

Clay Bavor, vice president of virtual reality at Google, said more than 50 million apps have been downloaded for Google Cardboard to date. He also announced an expansion of VR to Android and a new platform for high quality VR on mobile devices, called Daydream, that's expected to be released this fall.